1. Field of the Invention
This invention relates to an apparatus, method and system for fabricating highly segregated magnetic grains on a substrate and more particularly relates to a guide method for selecting segregant materials which produce improved magnetic characteristics.
2. Description of the Related Art
Hard-disk drives provide data storage for data processing systems in computers and servers, and are becoming increasingly pervasive in media players, digital recorders, and other personal devices. Advances in hard-disk drive technology have made it possible for a user to store an immense amount of digital information on an increasingly small disk, and to selectively retrieve and alter portions of such information almost instantaneously. Particularly, recent developments have simplified hard-disk drive manufacture while yielding increased track densities, thus promoting increased data storage capabilities at reduced costs.
In a hard-disk drive, rotating high precision aluminum or glass disks are coated on both sides with a special thin film media designed to store information in the form of magnetic patterns. Electromagnetic read/write heads suspended or floating only fractions of micro inches above the disk are used to either record information onto the thin film media, or read information from it.
A read/write head may write information to the disk by creating an electromagnetic field to orient a cluster of magnetic grains, known as a bit, in one direction or the other. To read information, magnetic patterns detected by the read/write head are converted into a series of pulses which are sent to the logic circuits to be converted to binary data and processed by the rest of the system. To increase the capacity of disk drives, manufacturers are continually striving to reduce the size of bits and the grains that comprise the bits.
The ability of individual magnetic grains to be magnetized in one direction or the other, however, poses problems where grains are extremely small. The superparamagnetic effect results when the product of a grain's volume (V) and its anisotropy energy (Ku) fall below a certain value such that the magnetization of that grain may flip spontaneously due to thermal excitations. Where this occurs, data stored on the disk is corrupted. Thus, while it is desirable to make smaller grains to support higher density recording with less noise, grain miniaturization is inherently limited by the superparamagnetic effect.
As the Hard-Drive industry is transitioning to perpendicular recording technology, adjustments are being made to adapt the disk media so that the magnetic c-axis (or easy axis) of the Cobalt alloy grows perpendicular to the disk plane. Most media manufacturers now rely on a Cobalt alloy with the incorporation of an oxide segregant to promote the formation of small and uniform grains. Researchers have observed that perpendicular media tends to grow rougher than its longitudinal counterpart. Further, researchers have discovered that rougher media creates a product with superior magnetic performance. So far no methods have been proposed that attempt to address the origin of the nanoscale roughness of perpendicular recording media. Therefore, researchers are left to search for satisfactory segregrants that provide the desired magnetic performance and corresponding media roughness using trial and error.
A rough recording media, though superior magnetically, has much deeper valleys between the magnetic grains than smooth recording media. This creates a perpendicular recording media with corrosion and flyability performance problems.
Accordingly, a need exists for a practical, attainable apparatus, system, and method for selecting a segregant material which will produce a magnetic recording layer with highly segregated magnetic grains to enhance the magnetic performance. Beneficially, such an apparatus, system and method would cooperate with the overcoat layer to reduce corrosion and improve flyability performance. Such apparatuses, systems and methods are disclosed and claimed herein.